U.S. Pat. No. 5,310,948 discloses a method to produce .alpha.-.beta. unsaturated carboxylic acids from epoxies by carbonylation and then dehydration of a .beta.-propiolactone intermediate. The catalyst system used includes a source of cobalt and a hydroxyl-substituted pyidine compound.
Aldehydes are produced according to U.S. Pat. No. 4,209,467, by hydroformylation of olefins using a catalyst which is a reaction product of a cobalt carbonyl compound and a hydroxy substituted pyridine compound.
A promoted and reduced combination of molybdenum oxide and antimony oxide is disclosed in U.S. Pat. No. 3,892,794 as being a useful catalyst for oxidation of olefins to unsaturated aldehydes and acids. Tin is disclosed as an effective promoter for this catalyst system. Although the carboxylic acids can be made directly from the olefin feed stock, conversion and yields of the carboxylic acids are not high.
It would therefore be desirable to have a process to produce .alpha.-.beta. unsaturated carboxylic acids wherein the yields and conversions are high, and wherein the process is a one stage process. It is therefore an object of the present invention to provide such a process.